This invention relates to paper feeders for successively feeding stacked sheets of paper, one by one, and is usable with a facsimile, a copying machine or the like.
Generally, in a facsimile apparatus, a plurality of sheets of paper are supplied in a stacked form and are fed in succession, one by one, for transmission. A paper feeder is disclosed in U.S. Pat. No. 4,085,929 which is usable with such device, and which comprises an inclined feed table on which a stack of paper sheets are placed. The stack of sheets is slidable along the feed table, under gravity, and into engagement with a feed roller which feeds the sheets forwardly in substantially the same direction that they move when they are brought into engagement with the feed roller.
An endless separator belt is arranged close to the feed roller and is in rotatable, pressure contact therewith, to run in a direction which is opposite to that in which the adjacent side of the feed roller proceeds. The belt pushes back all of the paper sheets other than the bottom one, thus allowing only the bottom sheet to be fed forward. Further, presser belt means are provided to press down the leading edges of the sheets other than the bottom one to prevent these sheets from being turned up at their leading edges or being raised partly in the vicinity of the feed roller under the effect of the separator belt running over the feed roller in the direction opposite to the direction of feed. There is no possibility that some sheets other than the bottom one cannot be smoothly fed forward even when engaged by the feed roller.
It has been found, however, that such previous form of paper feeder involves a disadvantage. If the number of paper sheets in a stack is increased freely, the correspondingly increased gravity component urges the sheets along the inclined feed table to the sheet-feeding region and may cause the separator and presser belts to yield under the pressure of the stacked sheets. This, combined with increase in friction between adjacent sheets, makes it difficult to feed the sheets separately one after another. In other words, if the number of stacked paper sheets exceeds a definite limit, the separator and presser belts become unable to function as intended and a plurality of sheets may be fed at a time. The previous paper feeder is thus subject to the disadvantage that the number of paper sheets in each stack laid on the feed table must be limited to a definite level for satisfactory operation.